Tremolo switching circuits in electric musical instruments



Feb. 20, 1951 J. R. VAN WYE 2,542,065

TREMOLO SWITCHING CIRCUITS IN ELECTRIC MUSICAL INSTRUMENTS Filed Jan. 3, 1949 2 Sheets-Sheet 1 JOHN R. VAN ME I BY QM 0 655 A, mofidamo Q on! 7 0 53m; 20 uu 3055 :22 T H zo Co 32.55% N 0E 9. 3.350 @048 wzoh Q 09. oh 1 9 0 655 r 9 Q9. A w 1954.80 :0 to 0 655. 85:5 3255. W M 92029. J 3 5:8 op 3255 222 3536 E38 wzoh 09. 0?

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tremolo is usually desirable for Patented Feb. 20, 1951 TREMOLO SWITCHING CIRCUITS IN ELEC- TRIC MUSICAL INSTRUMENTS John R. Van Wye, Cincinnati, Ohio, assignor to The Baldwin Company, Cincinnati, Ohio, a corporation of Ohio Application January 3, 1949, Serial No. 69,013

9 Claims.

My invention relates generally to polyphonic keyboard electric musical instruments of the organ type wherein electric oscillations corresponding to musical tones are generated, collected and/or modified as to harmonic content and converted to sound by an electro-acoustic system. In particular, my invention relates to the problem of simulating the effects usually available in pipe organs, wherein an amplitude tremolo or frequency tremolo (vibrato) may be provided in the tones produced by one division of the organ normally associated with one keyboard or one set of playing keys to the exclusion of tones produced by other divisions normally associated with other keyboards or sets of keys. Specifically, a tremolo is seldom applied to bass notes (pedal keyboard) in pipe organs whereas certain solo voices. 1

Heretofore in electric musical instruments of the above type wherein all oscillations of a given fundamental frequency are derived from a single generator, vibrato has been attained by the application of tremolo voltages to all such gener ators or their outputs through a main switch, making it impossible to provide at the same time a vibrato voice and a voice free of vibrato, as for example a vibrato melody played on one keyboard and an accompaniment played on another keyboard but without vibrato or tremolo.

Therefore, it is an object of my invention to provide circuits in electric musical instruments whereby the tremolo may seem to be limited to the tones derived through individual keyboards or sets of playing keys.

Another object of my invention is to provide electric circuits whereby tremolo may be applied either to all generators in an electric musical instrument or only to selected generators in accordance with the desire of the operator.

Still another object of my invention is to provide'circuits as in the preceding objects, which are useful either in instruments wherein octavely related generators are connected in cascade or to instruments wherein all generators operate independently of each other so far as the frequency of'the oscillations is concerned.

'These and other objects, which will be set forth hereinafter or will be apparent to those skilled in the art upon reading these specifications, I accomplish by those circuits and arrangements of parts of which I shall now set forth exemplary embodiments. Reference is made to the drawings forming a part hereof and wherein:

Figure 1 is a circuit .diaaram embodying my invention as applied to an instrument employing cascaded generators;

Figure 2 is a modified form of the circuit of Figure l, adapting my invention to an instrument wherein the generators are not cascaded;

Figure 3 shows an alternate circuit embody ing my invention, but applicable to instruments employing cascaded generators;

Figure 4 is a circuit diagram of still another embodiment of my invention; and

Figure 5 is a main switching circuit which may be employed as an alternate to the switching circuits of Figures 1 and 2.

In instruments of the type to which my invention relates, it is the usual practice to direct oscillations from the generators through key switches and into a separate header or headers for each keyboard. It is readily possible to provide amplitude tremolo for notes played on one keyboard to the exclusion of those played on another, by the use of variable impedance or other means connected to each such header. However, the introduction of frequency tremolo or vibrato to oscillations collected in a header of a keyboard requires devices, such as that disclosed by Hanert in U. S. Patent No. 2,382,413,

which are not only costly to produce but necessitate the use of rotating condensers, or other moving devices, which are potential sources of service problems. It is comparatively inexpensive to provide a single source of voltage pulsating at a sub-audio rate and achieve a vibrato or frequency tremolo by connecting this source to all generators or to the master generators of the various cascade series. However, when this is done all voices produced will be characterized by vibrato.

My invention provides a simple, practical solution to the problem by the employment of the following concept: If, when a vibrato voice and a non-vibrato voice are desired simultaneously, instead of applying a vibrato voltage to all generators, or a tremolo to the header or headers of the particular keyboard on whose notes a tremolo is desired, an auxiliary key switch is provided under each key so that a tremolo voltage may be applied only to those generators (or to those master generators controlling the frequency of octavely related generators of a cascade series) selected by keys in that keyboard, I may play notes with tremolo on such keyboard, while securing the effect of notes without tremolo from another keyboard. It is true that if I play, for example, middle C with tremolo on one keyboard. I will also set a tremolo on middle C of the other keyboard (and on all Cs a cascaded system wherein the tremolo is applied to a master generator which controls the lrquency of other C generators); however, the tremolo on the middle C of the other keyboard is masked since it heard simultaneously with the tremolo on the note of the first keyboar-c, while noes played on the other keyboard which are not of the same nomenclature will be reproduced without tremolo. As is usually the case, there are several notes being played simultaneously in an accompaniment while only a single note is bcing played as part of the melody, or solo. For example, if a note (3- is played as part of a solo on one keyboard, the notes C, E and G may be played simultaneously on another as the accompaniment. A tremolo applied to the solo G will occur also in the accompaniment G, unless the latter octavely displaced from the former in a system wherein the G generators are not cascaded. Yet, the C and notes in the accompaniment will not have a tremolo; over-- all auditory effect will be that of a solo G with tremolo played on one keyboard and an accompaniment chord C, E and G without tremolo played on another keyboard.

The objects of my invention may be attained by the employment of various types of circuits.

In the embodiment illustrated in Figure 1 oscillation generators B1 C are two of a series of twelve master generators, corresponding to the twelve half tones of a musical scale, to which are respectively connected, in cascade, as known in the art, octavely related generators such as B2 and C2, B3 and C3 (not shown) and other octavely related generators for as many ctaves as are covered by the instrument. The dot-dash lines such as i and 2 diagrammatically indicate control of the frequencies generated at the cascaded generators by master oscillators B1 and C1 respectively. As is known in the art, this control may be electronic], magnetic, or mechanical desired. In a manner similar to that taught by Kock in. United States Patent No. 2,233,948, oscillations from generators such' as B1 and C1 are transmitted through decoupling resistors such as 3 and 4, respectively, and key switches 5 and 6, respectively, to oscillation collecting headers such as l. Octavely related s" cillations may be simultaneously collected by additional headers, if so desired, in a manner taught by in the above patent. However, for simplicity such circuits are omitted from the drawings. Key switches such as 6 may be associated with one keyboard, designated in Figure l K'tD #2 while similarly function-- ing switches such as 3 and ii in another keyboard, "lesignated as KBD #i, transmit oscillations from the same generators to a header it") asso iated with 151313 Additional similar switches (omitted to simplify the diagram) for other keyboards may be connected in a manner similar to switches of E1313 #1 and K133 In the manner shown by Koch, oscillations collected by headers such as l and Ill may be transmitted to tone color circuits an output s 1 instruments wher in the tremolo voltage or other tremolo'producing vehicle is applied to all generators only by means of a main switch it will be obvious that notes produced by play According to one embodiment of my invention, I employ additional key switches, such as l i it, actuated substantially simultaneously with key switches 5, fl, 8 and 8 respectively by the same keys. The key tremolo switches i2 and conpost the generator C1 to tremolo headers l5 and res iectively, which in turn are connected to keyboard selector switches H and I8, respectively, as shown. In a similar manner key tremolo switches It and i3, and other similar switches, connect their respective generators with the headers i5 and lb. The respective On and O1? terminals of the switches i? and it are connected by leads l9 and 2! to which may also connected additional keyboard tremolo switches for other keyboards (not shown). To the lead may be connected a lead 2! from a suitable tremolo oscillator 2 Also in connection with the lead 21 is one terminal of a main tremolo switch 23, the other terminal of which may be connected through the lead 24 to the lead Hi. Thus, when the keyboard selector switches ll and 18 are in an Off position, a tremolo voltage may be made available simultaneously to all generators such as B1 and C1 by means of the main tremolo switch However, when the switch 23 is in an Off position the tremolo voltage may be connected to either the tremolo header 15 or the tremolo header to by the closure of switches ll or l8 respectively,

esignated also KBD #2 Tremolo and KBD #1 Tremolo. It will be obvious that with such a circuit it will be possible to play a note such as B1 on KBD without having tremolo on a note such as C1 played on KB'D #I and other keyboards (not shown).

In order that a tremolo can be made available in notes such as B2 and C2, key tremolo switches such as 25 and 26, connected to the header I5, are connected also to respective auxiliary headers 2'! and 28 in order that tremolo voltage may be applied to the corresponding master generators B1 and C1 respectively. It will be apparent, then, that in an instrument of the type illustrated in Figure 1, key switches corresponding to all C generators will be connected to the header 28. Additional similar headers (not shown) will, of course, be required for the remaining master generators (not shown).

My invention as applied to an instrument wherein octavely related oscillation generators are not cascaded may take the form illustrated in'Figure 2. This circuit is similar to the circuit of Figure 1 with the exception of the omission of headers such as 21 and 28 and the connection of switches such as 29 and 30 directly to corresponding generators such-as B2 and C2. (Oscillation switching and collecting circuits have been omittedfor simplicity from this diagram, but it will be understood that they will be employed with the circuit of Figure 2 and may be similar to those shown in Figure 1.)

It will be apparent that" tremolo key switches such as H and I2 in Figure 1, and 29 and 30 in Figure 2, will be required under all keys of an instrument, if it is desired that tremolo be made available on all notes by means of a main tremolo switch such as 23 in Figure 1. If, on the other :hand, it is desired that tremolo be available to selected keyboards or portions of keyboards for solo purposes and alternatively available on all notes of the instrument by means of a main control, a circuit such as that illustrated in Figure 3 may be employed. In this embodiment of'my invention, key tremoloswitches such as 31 and 32 are connected to corresponding generators such as B1 and C1 in a manner similar to that of Figure 1. However, the tremolo headers 33 and 34 are connected as shown in Figure 3 through switches 35 and 36 respectively to the source of tremolo voltage. The main tremolo, for all the notes of such an instrument, is applied to all master generators such as B1 and C1 substantially simultaneously through a multiple switch of any suitable kind, indicated generally at 31. This switch may be of the type disclosed by Raymond P. Mork in U. S. Patent No. 2,498,569, and is so illustrated. The movement of a plunger 38 upwardly closes successive contacts 39, 39a, etc. mounted on the respective leaves 40a, 4027, etc., thereby transmitting a tremolo voltage through a leaf 40 and its contact 4! to the respective master generators such as B1 and C1, and acting in the On position to connect all generators to the tremolo voltage.

Although the circuit of Figure 3 has thelimitation that it applies, for all practical purposes, only to cascaded generator instruments unless a complicated switch is employed (because one leaf is required for each independent generator or series of generators), it has the advantage that tremolo switches such as 3i and 32 need only be employed in conjunction with those playing keys corresponding to notes on which a solo tremolo is to be made available. It will be apparent that the omission of a series of switches containing such ones as 42 and 43 and the omission of the corresponding keyboard tremolo switch 36, will not preclude the application of tremolo to all master oscillators, when desired, because tremolo voltage in this case is applied to the generators directly through the main tremolo switch 31.

In Figure 4 is shown an alternate circuit by means of which a tremolo may be made available to all generators via a main switch even though tremolo key switches are not employed in conjunction with all the keys of an instrument. This circuit, as in the case of the circuit of Figure 3, is of utility in instruments in which the octavely related generators are connected in cascade. Single-pole, double-throw, key tremolo selector switches, such as those indicated generally at 44 and 45, as and 45, are actuated (downward) respectively by octavely related playing keys simultaneously with key switches such as 5 and 25 in Figure 1, which have been omitted for the sake of simplifying the circuit of Figure 4. Tremolo voltage from a source 45 may be applied as shown to master generators such as B1 and C1 through a main tremolo switch 4?, a header 48 and the upper contacts of the switches such as 44 and 45, 49 and 50 and their primed counterparts. lhe switches 44 and 45 are two of a series associated with a first keyboard while switches such as 49 and 56 may be associated with a second keyboard. Keyboard tremolo selector switches El and 52 are associated with a first and second keyboard respectively and are connected as shown to headers such as 53, 53 through which tremolo voltage may be transmitted to the contacts of switches such as 44, 45 and their primed counterparts, and to headers such as 54, 55' through which tremolo voltage may be transmitted to the lower contacts of switches such as 49, 50, and their primed counterparts.

It will be apparent that with a circuit such as that of Figure 4, switches such as 49, 58 may be omitted without precluding the application of tremolo voltage to all generators if so desired via the main tremolo switch 41. A further limitation of this circuit is that if all switches such as 44 and 45 for octavely related generators are keyed simultaneously, no tremolo will be applied to their master generator. This limitation is not considered a serious one in plural manual organs because in organs there are usually a minimum of five octavely related keys in a given keyboard and only four can be depressed simultaneously by the fingers of two hands.

It will be seen from this circuit that if the main tremolo switch 4? be closed, the tremolo voltage will be applied to the several generators through the upper contacts of the double-throw key tremolo switches so long as any of them remain in the non-actuated position. If, however, the main tremolo switch 4'! is opened and the tremolo switch 5| for keyboard #l is closed, then upon the actuation of any keyboard switch of the group 44, 45 and their primed counterparts the tremolo voltage will be fed to the generator group to which that switch is connected, but not to other generator groups unless key switches connected to them be also actuated. Thus, so long as the tremolo switch 52 of the keyboard #2 remains open, notes other than those being played on keyboard #1 may be played on keyboard #2 without the tremulant effect. The reverse condition will obtain if switch 52 be closed and switch 5| opened.

Yet another system for connecting a main tremolo switch and keyboard tremolo switches for use with circuits such as those illustrated in Figures 1 and 2 is shown in Figure 5. Tremolo voltage from a source 54 may be applied to KBD it! or KBD #2 through keyboard tremolo switches 55 or 53 respectively or to both KBD #i and #2 via a main double-pole, single-throw tremolo switch 51. The headers 58 and 58 correspond respectively to headers 15 and 16 of Figure 1. Switches such as 50 and ti correspond respectively to switches I2 and it of Figure 1.

My invention is not limited to instruments having different sets of tone-color circuits for different keyboards. It may also apply, for instance, to instruments wherein a keyboard may be divided so as to provide different registers for the respective divisions thereof.

Additional modifications may be made in my invention without departing from the spirit of it. Having thus described my invention in certain exemplary embodiments, what I claim as new and desire to secure by Letters Patent is:

1. In an electric musical instrument. main generators, a plurality of keyboards, key switch means for deriving oscillations from said main generators in separate headers for said keyboards respectively, a source of tremolo voltage effective when applied to said main generators to impart tremolo to the oscillations produced thereby, and

means including key switches associated with a,

keyboard for connecting said source to said generators selectively, whereby tremolo is obtained with respect to derived oscillations only when' keys for said oscillations are depressed in the keyboard so equipped.

2. In an electric musical instrument of the type wherein electric oscillations from the same series of generators are selectively transmitted to an output system through key switches associated respectively with keys in a plurality of keyboards, a source of tremolo voltage effective when applied to said generators to impart tremolo to the respective oscillations produced thereby, a plurality of tremolo switches associated with and actuatable respectively by the keys of at least one keyboard, a main tremolo switch connecting said 7 source with all said generators, and at least one keyboard tremolo switch connecting said source with said generators through respective tremolo switches of a single keyboard.

3. The combination set forth in claim 2, wherein said source is connected by said main tremolo switch to said generators through respective key tremolo switches which are of double-throw type.

4. In an electric musical instrument of the type wherein electric oscillations from each generator in a plurality of series of cascaded generators are selectively transmitted to an output system through key switches associated respectively with keys in a plurality of keyboards, a source of tremolo voltage effective when applied to each of said series to impart a tremolo to respective oscillations produced thereby, a plurality of tremolo switches associated with and actuatable respectively by the keys of at least one keyboard, a main tremolo switch connecting said source with each of said series of generators, and at least one keyboard tremolo switch connecting said source with said plurality of series of generators through respective tremolo switches of a single keyboard.

5. In an electric musical instrument of the type wherein electric oscillations from each generator in a plurality of series of cascaded generators are selectively transmitted to an output system through key switches associated respectively with keys in a plurality of keyboards, a source of tremolo voltage effective when applied to each of said series to impart a tremolo to respective oscillations produced thereby, a plurality of tremolo switches associated with and actuable respectively by the keys of at least one keyboard whereby the application of said tremolo voltage may be made selectively to said series of generators, and a main tremolo switch for connecting said source with all of said series of generators simultaneously.

6. In an electric musical instrument, generators for musical tones, a source of tremolo voltage which, applied to said generators, will produce vibrato in said tones, and circuits containing switches for making said application, one such circuit having portions common to all of said generators and containing a switch for applying said voltage to said generators simultaneously, and another such circuit including switches operated by playing keys for applying said tremolo voltage selectively to certain of said generators as said key switches are actuated.

'7. The structure claimed in claim 6 wherein said instrument has a plurality of keyboards, and

a tremolo voltage header for each such keyboard, said first mentioned circuit containing switching means for energizing all such tremolo voltage headers simultaneously, and said second mentioned circuit mean containing selective switch mechanism for energizing said headers selectively, said headers having connection with said gencraters through said key switches.

8. The structure claimed in claim 6 wherein said instrument has a plurality of keyboards, tremolo voltage headers for each such keyboard, wherein said first mentioned circuit comprises a multiple switch having connections to the several generators and a connection to said source of tremolo voltage, and wherein said second mentioned circuit has individual switching means for energizing said several tremolo headers, said headers having connection with said generators through said key switches.

9. In an electric musical instrument of the type wherein electric oscillations from each generator in a plurality of series of cascaded generators are selectively transmitted to an output system through key switches associated respectively with keys in a plurality of keyboards, each of said cascaded series comprising a master generator and octavely-related controlled generators; a source of tremolo voltage effective when applied to each of said master generators to impart a tremolo to respective oscillations produced thereby; a. plurality of tremolo switches associated with and actua'table respectively by the keys of at least one keyboard; a main header for said one keyboard; a plurality of auxiliary headers for said one keyboard; a main tremolo switch connecting said source with each of said master generators, said last mentioned connection comprising connections between said source and said main header, connections between said main header and said auxiliary headers through respective tremolo switches, and connections between said auxiliary headers and said master generators respectively; and at least one keyboard tremolo switch connecting said source with said main header.

JOHN R. VAN WYE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,30l,87l Hanert Nov. 10, 1942 2,310,429 Hanert Feb. 9, 1943 

